package total;

import java.util.Scanner;

/**
 * A particle has initial velocity and constant acceleration. 
 * If its velocity after certain time is v then what will its displacement
 *  be in twice of that time?
 * @author chenxiaokang
 *
 */
public class Ques1023 {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		while(scan.hasNext()){
			int a = scan.nextInt();
			int b = scan.nextInt();
			System.out.println(a * 2 * b);
		}
	}
}
